CN1310283C - Calibration method of scanning tool for semiconductor and its standard calibration sheet - Google Patents

Abstract

The invention relates to a method for correcting a scanning tool for a semiconductor and a standard correction sheet for correcting the scanning tool. Then, a scanning tool is used to scan the standard pattern on the wafer to obtain a signal which shows the position of the side wall of the standard pattern, and the scanning tool can be corrected in the X direction, the Y direction and the Z direction by using the signal. The method of the present invention can correct the scanning tool in X direction and Y direction and also in Z direction, and this can improve the problem of deviation of the scanning tool caused by the failure of correcting the Z direction.

Description

Calibration method of scanning tool for semiconductor and its standard calibration sheet

technical field

The present invention relates to a method for calibrating a scanning tool in a semiconductor device field or a method for manufacturing or processing a semiconductor and a standard calibrating sheet thereof, in particular to a scanning electron microscope matching (match) and calibrating (calibration) A method for calibrating a scanning tool for semiconductors and a standard calibration sheet for calibrating the scanning tool.

Background technique

Usually in the semiconductor process, after some process steps, a scanning electron microscope (SEM tool) is used to observe whether the pattern on the wafer is consistent with the expected target. Moreover, when using a scanning electron microscope to observe wafer patterns, usually a standard calibration sheet is used to match and calibrate the scanning electron microscope to ensure the results presented by the scanning electron microscope No deviation will occur.

The general calibration method of the scanning electron microscope is to use a standard calibration sheet with a standard pattern. Please refer to FIG. 1 , which is a schematic cross-sectional view of a known standard calibration sheet for calibrating a scanning electron microscope. The existing standard calibration sheet is composed of a wafer 100 and a film layer 102 on the wafer 100, and the film layer 102 has a standard pattern 104a or 104b. In particular, the sidewalls of the standard pattern 104a or 104b are vertical sidewalls. Afterwards, the wafer 100 is placed in a scanning electron microscope for scanning, and the signal (as indicated by the arrow) reflected on the edge of the standard pattern 104 a or 104 b can be obtained. Then, the obtained signal value is used for calibration of the scanning electron microscope.

However, when using the corrected scanning electron microscope to observe the film layer with the contact window opening after correcting by the above method, obvious deviation still occurs. This is because, usually, the outline of the opening of the contact window formed in the film layer will shrink from top to bottom, and the size of the bottom of the opening of the contact window is the key dimension. However, the calibration and matching of the existing standard calibration sheets can only be performed on the surface of the standard pattern, that is, the positions in the X and Y directions, but cannot be corrected and matched in the Z direction (the direction of depth). Therefore, if the existing standard calibration sheet is used for calibration, there will still be deviations when using the calibrated scanning electron microscope to observe the opening of the contact window.

It can be seen that the above-mentioned existing calibration method for scanning tools for semiconductors and the standard calibration sheet used for calibrating scanning tools still have many defects, and further improvement is urgently needed. In order to solve the defects of the existing calibration methods and their standard calibration sheets, the relevant manufacturers have tried their best to find a solution, but no suitable design has been developed for a long time. This is obviously a problem that the relevant industry is eager to solve .

In view of the defects in the above-mentioned existing calibration methods and their standard calibration sheets, the inventors have actively researched and innovated based on years of rich practical experience and professional knowledge in the design and manufacture of such products, in order to create a new semiconductor calibration device. The scanning tool calibration method and the standard calibration sheet used for calibrating the scanning tool can improve the general existing calibration method and the standard calibration sheet, making it more practical. Through continuous research, design, and after repeated trial samples and improvements, the present invention with practical value is finally created.

Contents of the invention

The main purpose of the present invention is to overcome the defects of the existing scanning tool calibration method and its standard calibration sheet, and provide a new semiconductor scanning tool calibration method and its standard calibration method for calibrating scanning tools. The main technical problem to be solved is to make it possible to solve the problem of deviation due to the inability to correct and match the Z direction after the scanning electron microscope is calibrated using the existing known calibration method and its standard calibration sheet. , so that it is more suitable for practical use and has industrial utilization value.

The purpose of the present invention and the solution to its main technical problems are achieved by adopting the following technical solutions. A calibration method for a semiconductor scanning tool according to the present invention comprises the following steps: providing a wafer with a standard pattern, wherein the sidewall of the standard pattern is slope-shaped; and scanning the wafer with a scanning tool The standard pattern on the wafer is used to obtain a signal, which shows the position of the sidewall of the standard pattern, and the scanning tool can be calibrated in X direction, Y direction and Z direction by using the signal.

The purpose of the present invention and the solution to its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned method for calibrating a scanning tool for semiconductors, the wafer is a test wafer.

In the aforementioned method for calibrating a scanning tool for semiconductors, the wafer is a product wafer.

The aforementioned method for calibrating a scanning tool for semiconductors, wherein the scanning tool is a scanning electron microscope.

In the aforementioned method for calibrating a scanning tool for semiconductors, the standard pattern is an opening pattern, and the opening pattern is an opening pattern that shrinks from top to bottom.

In the aforementioned method for calibrating a scanning tool for semiconductors, the standard pattern is a raised pattern.

The purpose of the present invention and its main technical problems are solved by adopting the following technical solutions. According to the present invention, a standard calibration sheet for calibrating scanning tools is used to calibrate a scanning tool for semiconductors. The standard calibration sheet includes: a wafer; and a standard pattern configured on the wafer. Wherein the side wall of the standard pattern is slope-shaped, and the size of the standard pattern is a key dimension, and the standard pattern is a raised pattern or an opening pattern, wherein the opening pattern is an opening that shrinks from top to bottom pattern, the dimension of the bottom of the opening pattern is the critical dimension.

The purpose of the present invention and the solution to its technical problems can also be further realized by adopting the following technical measures.

The aforementioned standard calibration sheet for calibrating scanning tools, wherein the wafer is a test wafer

In the aforementioned standard calibration sheet for calibrating scanning tools, the wafer is a product wafer.

Compared with the prior art, the present invention has obvious advantages and beneficial effects. As can be seen from the above technical solutions, in order to achieve the aforementioned object of the invention, the main technical contents of the present invention are as follows:

The present invention proposes a method for calibrating a scanning tool used in semiconductors. The method firstly provides a wafer with a standard pattern, wherein the sidewall of the standard pattern is slope-shaped. Then use a scanning tool to scan the standard pattern on the wafer to obtain a signal that shows the position of the sidewall of the standard pattern, and use the signal to scan the scanning tool in the X direction, Y direction and Z direction Correction.

Because the method of the present invention can not only correct the scanning tool in the X direction and the Y direction, but also correct the Z direction, it can improve the problem that the scanning tool still has deviations due to the inability to correct the Z direction in the prior art.

The present invention also proposes a standard calibration sheet, which is used to calibrate a scanning tool for semiconductors. The standard calibration sheet is composed of a wafer and a standard pattern arranged on the wafer, wherein the side of the standard pattern The walls are sloped and the size of the standard pattern is a critical dimension. If the standard pattern is an opening pattern, the opening pattern is reduced from top to bottom, and the bottom dimension is the critical dimension.

Since the present invention designs the standard pattern of the standard calibration sheet as a standard pattern with a slope-shaped side wall, the scanning tool can be calibrated in the X direction, the Y direction and the Z direction through the design of the slope-shaped side wall, so the present invention can be solved. Some correction methods will produce obvious deviations because they cannot correct the Z direction.

In summary, the calibration method of the special semiconductor scanning tool of the present invention and the standard calibration sheet used for calibrating the scanning tool can solve the problem of the existing calibration method and the standard calibration sheet calibration of the scanning electron microscope due to the inability to correct the scanning electron microscope. There is still a problem of deviation when correcting and matching the Z direction. It has the above-mentioned many advantages and practical value, it is indeed innovative in the calibration method and product structure, and has great improvements in the method, structure or function, and has improved efficacy compared with the existing calibration method and its standard calibration sheet, and There is great progress in technology, so that it is more suitable for practical use, and has wide application value in industry. It is a novel, progressive and practical new design.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a known standard calibration sheet for calibrating a scanning electron microscope.

FIG. 2 is a schematic cross-sectional view of a standard calibration sheet for calibrating a scanning electron microscope according to a preferred embodiment of the present invention.

FIG. 3 is a schematic diagram of signals for scanning electron microscope calibration using the standard calibration sheet in FIG. 2 .

FIG. 4 is a schematic cross-sectional view of a standard calibration sheet for calibrating a scanning electron microscope according to another preferred embodiment of the present invention.

FIG. 5 is a schematic diagram of signals for scanning electron microscope calibration using the standard calibration sheet in FIG. 4 .

100, 200: wafer 102, 202: film layer

104a, 104b: standard pattern 204, 204a: standard pattern

206, 206a; side wall 302, 304: crest signal

502, 504: peak signal 310a, 310b: starting point of peak signal

510a, 510b: the beginning of the crest signal 312a, 312b: the end of the crest signal

512a, 512b: the end of the peak signal D: critical dimension

Detailed ways

Below in conjunction with the accompanying drawings and preferred embodiments, the specific calibration method, steps, structure, features and efficacy of the calibration method for the semiconductor scanning tool proposed according to the present invention and the standard calibration sheet for calibrating the scanning tool, Details are as follows.

In order to solve the problem that the existing standard pattern can only correct the position in the X direction and the Y direction because the side wall is vertical, but cannot correct the Z direction. When scanning the contact window opening pattern with a scanning tool, it will still To solve the problem of deviation, the present invention particularly proposes a calibration method for scanning tools used in semiconductors and a standard calibration sheet for calibrating scanning tools. The standard pattern on the standard calibration sheet has a slope-shaped side wall. Therefore, the standard In addition to correcting and matching the positions in the X direction and the Y direction, the pattern can also correct and match the Z direction. The details are as follows.

Please refer to FIG. 2 , which is a schematic cross-sectional view of a standard pattern on a wafer according to a preferred embodiment of the present invention. The standard calibration sheet for calibrating scanning tools of the present invention includes a wafer 200 and a film layer 202 on the wafer 200 , wherein the film layer 202 has a standard pattern 204 therein. In a preferred embodiment, the film layer 202 is, for example, a dielectric layer or a conductive layer, preferably a dielectric layer. The standard pattern 204 is, for example, an opening pattern, and the sidewall 206 of the standard pattern 204 is slope-shaped.

Here, the sidewall 206 of the standard pattern 204 is slope-shaped, and the standard pattern 204 is an opening pattern that shrinks from top to bottom. In other words, the bottom dimension is smaller than the top dimension, and the bottom dimension D of the standard pattern can be set as the critical dimension of the process (eg, the critical dimension of the contact window opening).

Please refer to FIG. 3 , which is a schematic diagram of signals for scanning electron microscope calibration using the standard calibration sheet in FIG. 2 . When the standard calibration sheet in FIG. 2 is placed in a scanning tool (such as a scanning electron microscope) to scan for calibration and matching, peak signals 302 and 304 will be measured at the sidewall 206 corresponding to the standard pattern 204, The peak signals 302, 304 represent the position of the opening pattern 204 from the top 310a, 310b to the bottom 312a, 312b. In more detail, the top portion 310 a corresponding to the opening pattern 204 is where the peak signal 302 starts, and the bottom portion 312 a corresponding to the opening pattern 204 is the end point of the peak signal 302 . Likewise, the portion 310b corresponding to the top of the opening 204 is where the peak signal 304 starts, and the portion 312b corresponding to the bottom of the opening 204 is where the peak signal 304 ends. Therefore, by the position of the beginning 310a, 310b of the peak signal 302, 304, the scanning electron microscope can be calibrated in the X direction and the Y direction, and by the position of the end 312a, 312b of the peak signal 302, 304 , the scanning electron microscope can be corrected in the Z direction, and the distance D between the ends 312a, 312b of the peak signals 302, 304 represents the dimension D of the bottom of the opening 204, which is the critical dimension of the process.

Therefore, if the standard calibration sheet of the present invention is used to calibrate the scanning electron microscope, in addition to the positions in the X and Y directions, the Z direction can also be corrected. In this way, when the scanning electron microscope calibrated by the standard calibration plate is used to scan the opening pattern of the contact window, the position of the opening of the contact window can be more accurately reflected, so that the opening of the contact window can be more accurately aligned with the conductive structure. alignment.

It is worth mentioning that the above-mentioned standard calibration sheet can be a test wafer or a product wafer. In other words, the standard calibration sheet can form the above-mentioned standard pattern on a blank wafer, or form the above-mentioned standard pattern on a specific position on a product wafer.

In addition, in the above embodiments, the opening pattern is used as the standard pattern for illustration. In fact, the standard pattern of the present invention may also be a raised pattern, as shown in FIG. 4 .

Please refer to FIG. 4 , which is a schematic cross-sectional view of a standard calibration sheet for calibrating a scanning electron microscope according to another preferred embodiment of the present invention. In FIG. 4 , the standard calibration sheet includes a wafer 200 and a standard pattern 204 a disposed on the wafer 200 , wherein the sidewall 206 a of the standard pattern 204 a is sloped.

Please refer to FIG. 5 , which is a schematic diagram of signals for scanning electron microscope calibration using the standard calibration sheet in FIG. 4 . When the standard calibration sheet in FIG. 4 is placed in a scanning tool (such as a scanning electron microscope) to scan for calibration and matching, the peak signals 502 and 504 can be measured at the corresponding side walls 206a, wherein the peak signals 502, 504 are locations showing raised patterns from bottom 510a, 510b to top 512a, 512b. Therefore, the scanning electron microscope can also be corrected in the X direction, the Z direction and the Z direction.

Since the present invention designs the standard pattern of the standard calibration sheet as a standard pattern with a slope-shaped side wall, the scanning tool can be calibrated in the X direction, the Y direction, and the Z direction through the structural design of the slope-shaped side wall, so it can be Solve the problem that the existing correction method will produce obvious deviation due to the inability to correct the Z direction.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the method and technical content disclosed above to make some changes or modifications to equivalent embodiments with equivalent changes, but any content that does not depart from the technical solution of the present invention, Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims (9)

1. A calibration method for a scanning tool for semiconductors, characterized in that it comprises the following steps: providing a wafer with a standard pattern, wherein the sidewalls of the standard pattern are sloped; and Use a scanning tool to scan the standard pattern on the wafer to obtain a signal, the signal determines the position of the side wall of the standard pattern, and use the signal to scan the scanning tool in the X direction, Y direction and Z direction correction. 2. The method for calibrating a scanning tool for semiconductors according to claim 1, wherein said wafer is a test wafer. 3. The method for calibrating a scanning tool for semiconductors according to claim 1, wherein said wafer is a product wafer. 4. The method for calibrating a scanning tool for semiconductors according to claim 1, wherein said scanning tool is a scanning electron microscope. 5. The calibration method for a semiconductor scanning tool according to claim 1, wherein the standard pattern is an opening pattern, and the opening pattern is reduced from top to bottom. 6. The method for calibrating a scanning tool for semiconductors according to claim 1, wherein said standard pattern is a raised pattern. 7. A standard calibration sheet for calibrating a scanning tool is a scanning tool for calibrating semiconductors, characterized in that the standard calibration sheet includes: a wafer; and A standard pattern configured on the wafer, wherein the sidewall of the standard pattern is slope-shaped, and the size of the standard pattern is a critical dimension, and the standard pattern is a raised pattern or an opening pattern, wherein The opening pattern is an opening pattern that shrinks from top to bottom, and the size of the bottom of the opening pattern is the critical dimension. 8. The standard calibration sheet for calibrating scanning tools according to claim 7, wherein said wafer is a test wafer 9. The standard calibration sheet for calibrating scanning tools according to claim 7, wherein said wafer is a product wafer.

Images